Optical instrument problems and solar technology
Answers are for parents and teachers.
1
A camera has F = 5 cm and Γ = 1/200. How far (in m) is the object? d = F(1 + Γ)/Γ.
10.05 m ≈ 10 m
2
A person can read a book only from 50 cm without spectacles. Which spectacles do they need? Find D (D₀ = 25 cm).
D = 1/0.25 – 1/0.5 = 2 dptr (convex)
3
A 3 m² panel receives 900 W/m² with 20 % efficiency. What is the power in W?
540
4
In a collector 80 kg of water warms by 25 °C (c = 4200). What is Q in J?
8400000
5
Why are the prospects of solar energy good in Uzbekistan?
Many clear days, long summer days and strong sunshine.